From 01b24fee285b098c74318a8be801ef3711ec18d7 Mon Sep 17 00:00:00 2001 From: Michael Buesch Date: Fri, 20 Feb 2009 15:38:49 -0800 Subject: spi_bitbang: add more lowlevel function documentation This adds more documentation of the lowlevel API to avoid future bugs. Signed-off-by: Michael Buesch Acked-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi_bitbang.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/spi/spi_bitbang.h') diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h index bf8de281b4ed..eed4254bd503 100644 --- a/include/linux/spi/spi_bitbang.h +++ b/include/linux/spi/spi_bitbang.h @@ -83,6 +83,13 @@ extern int spi_bitbang_stop(struct spi_bitbang *spi); * int getmiso(struct spi_device *); * void spidelay(unsigned); * + * setsck()'s is_on parameter is a zero/nonzero boolean. + * + * setmosi()'s is_on parameter is a zero/nonzero boolean. + * + * getmiso() is required to return 0 or 1 only. Any other value is invalid + * and will result in improper operation. + * * A non-inlined routine would call bitbang_txrx_*() routines. The * main loop could easily compile down to a handful of instructions, * especially if the delay is a NOP (to run at peak speed). -- cgit v1.2.1